1. Field of the Invention
The present invention elates generally to sliding doors and more particularly to a novel, sliding door roller apparatus having an improved, replaceable wheel assembly that can be easily removed and replaced with a new wheel assembly whenever a wheel breaks or wears out. The present invention eliminates the need to disassemble or reassemble the outer door frame while replacing the broken or worn out wheel. The present invention also includes an advantageous adjusting mechanism for positioning the wheel assembly within the door frame to allow the sliding door to be properly positioned within its door opening.
2. Description of the Prior Art
A sliding door is a well-known device in the art that generally includes an outer frame having top and bottom rollers or wheels that engage upper and lower tracks located in a door opening that guide the door's horizontal movement. The outer frame is generally constructed from roll-formed or extruded tubular shaped rails (the horizontal portion of the frame) and stiles (the vertical portion of the frame). The ends of the rails and stiles are usually mitered at 45.degree. angles and are press fitted onto corner brackets to form the four corner joints of the outer frame. After the rails and stiles have been joined, wire screening or glass can be placed within recessess located on the frame to form the sliding door.
Generally, a screen door is manufactured with its wheel or roller assemblies mounted within the top and bottom rails of the outer frame. Preferably, the wheel assemblies are mounted on the corner brackets that help form the corner joints since these brackets are usually made from steel and are much stronger than the rail portions that are usually made from lighter-weight material, such as aluminum. The wheels of the assemblies extend through openings formed in the rails for engagement with the upper and lower tracks.
Probably the most common problem associated with prior art sliding doors has been the breaking or wearing out of the wheels during usage. In order for a sliding door to properly move along its tracks, the wheels must be in good working condition. Therefore, even if a single wheel is broken, the other wheels usually cannot compensate for the broken wheel to maintain the continuous smooth sliding motion of the door on its tracks. Therefore, whenever a wheel breaks or wears out, it must be immediately replaced with a new wheel.
The replacement of a wheel on a prior art sliding door can be a very difficult job, especially if the sliding door has its wheel assemblies mounted on the corner brackets of the frame. Whenever a wheel breaks or wears out on such a unit, the outer frame usually has to be disassembled to reach and replace the broken wheel. If the sliding door is a screen door, the screening usually has to be at least partially removed from the frame before the frame can be disassembled. While the removal of the screening is usually an easy job, its later replacement back onto the frame can be very difficult.
Once the screening has been remove, the rails and stiles have to be disassembled to reach and remove the broken wheel. Usually, the wheel itself is not replaced, but rather, the entire wheel assembly that holds the wheel is removed and replaced with a new unit. One problem that can be encountered in replacing the wheel assembly is that replacement units are not always readily available in retail stores. Therefore, the door manufacturer may have to be contacted to obtain a properly fitting wheel assembly.
After the broken wheel or wheel assembly has been replaced, the stiles and rails have to be remounted on the corner bracket and the screening has to be placed back on the frame. If the screen door was originally made with machinery that stretched and attached the screening to the frame, the screening might not properly fit back onto the frame. If this occurs, the screening usually has to be stretched by hand to fit back into the recesses on the frame. However, it is possible that this stretching could cause distortion or create holes in the screening. Therefore, even if the screening could be replaced back onto the frame, it could lose its original appearance and shape.
As a result of the difficulty in replacing the wheels on prior art screen doors, most homeowners would rather continue using the screen door with the broken wheel than fix it. However, a broken wheel, especially a broken, bottom wheel, results in a sliding door that does not move very smoothly along its tracks. Also, the continued use of a door with a broken wheel can cause the other wheels to break prematurely or wear out faster than normal. Another possible alternative for the homeowner with a broken wheel is to replace the entire screen door with a new door, rather than fix the broken wheel. This is an often used alternative especially if the prior art screen door is a cheaply made product having a relatively low retail cost.
One prior art device described in U.S. Pat. No. 3,716,890 allows for the replacement of a broken wheel on sliding doors without the necessity to disassemble and reassemble the outer frame. However, this device requires the removal and replacement of a rivet that holds the wheel to its housing while the housing remains on the door frame. This manual replacement of the rivet is not only awkward but may require the need for a special rivet gun or other tool to properly fasten the wheel back to its housing. Even if an alternate fastener such as a nut and bolt is used, the nut can become loose during usage which can cause the wheel to become detached from its housing.
Another frequently encountered problem associated with a sliding door, especially a screen door, is partly attributed to its relatively low weight. Since a screen door seldom exceeds 10 pounds in weight, it has a tendency to jump from its tracks and jam, thus interfering with the smooth opening and closing of the screen door. This jumping problem is especially prevalent if either, or both, of the upper or lower tracks are bowed. When a track becomes bowed, there is a location along the tracks where the tracks are further apart than normal. If the tracks are far enough apart from each other, a space is created between the tracks which can cause a wheel to leave its track. This jumping problem especially occurs if one pushes or pulls on the light-weight door while sliding it across its tracks. When a wheel does leave its track, it must be immediately positioned back on its track to allow the door to slide smoothly again. The placement of the wheel back on its track is not always an easy task and can be quite frustrating to a home owner, especially if the wheel continually jumps from its track.
Various types of rollers or wheel assemblies have been suggested to maintain the wheels in proper contact with the tracks to avoid this jumping problem. On some prior art screen doors, the wheels can be moved outward from the frame to somewhat compensate for a bowed track. However, if the top and bottom wheels extend too far from the frame, there is a possibility that the sliding screen door could jam at locations where the top and bottom tracks are at their narrowest distance from each other. Either the top or bottom wheel would then have to be moved back into the frame. Therefore, it is not possible to alleviate the jumping problem by merely setting the top and bottom wheels at their maximum outward positions.
Other prior art devices alleviate this jumping problem by biasing the wheel assembly outward from the frame. The biasing means, typically a spring, maintains the wheel assembly outward from its frame so that the wheels remain in proper contact with its track. Whenever the wheels encounter a bowed portion along the tracks, the wheels move out to compensate for the widened opening between the tracks. Alternatively, whenever the frame encounters a narrow spot along the track, the wheels are pushed back inwards into the frame to compensate for the narrow alignment.
One problem associated with such spring biased roller assemblies is that the bottom supporting roller assemblies support the weight of the sliding door. The weight of the sliding door can cause the bottom wheels to move back to the farthest position within the door frame, especially if the force of the spring is not very large. If the wheels retract back into the door frame, it is possible that the bottom edge of the sliding door can contact the bottom surface of the door frame, thus interfering with the smooth sliding motion of the door. Therefore, although these prior art devices somewhat alleviate the jumping problem, they still lack some means to position the wheels and still properly support the door.
This problem of properly positioning the wheels within the frame of the sliding door is further increased if the bottom wheels are also used to position the side stiles of the sliding door with the side jambs of the door opening. Usually, a door opening is not always perfectly rectangular or the bottom or lower tracks will become warped or bowed from use. As a result, the screen door, which is capable of being manufactured with more precision, may be crooked or misaligned when placed in the door opening. When this occurs, the side stiles of the sliding door do not properly align with the side door jambs of the door opening. Even a slight misalignment of the screen door against the door jambs can create an opening large enough for insects to pass through. Thus, the purpose behind the use of a screen door is defeated, if insects, such as mosquitoes, fleas and bees, can easily pass through openings caused by an improperly aligned screen door.
The simple solution of this problem is to properly align the stiles of the sliding door with the door jambs. One way of doing this is to tilt one side of the screen door until proper vertical alignment is made with the door jamb. This alignment can be accomplished by raising or lowering one or both of the bottom wheels of the screen door. The raising or lowering of the bottom wheel is accomplished by either extending or retracting the wheel from its opening in the rail portion of the frame while the weight of the sliding door is borne by the wheel. This operation is referred to as adjusting the "height" of the wheel. The mechanism that sets the "height" of the wheels must be easily accessible to the user to permit the door to be properly positioned within the door opening.
The present invention has as its objective the elimination of the above-mentioned and additional disadvantages associate with conventional sliding door wheel or roller assemblies The present invention provides a sliding door roller apparatus with an advantageous replaceable wheel assembly that can be easily removed and replaced with a new wheel assembly without the need to disassemble and reassemble the frame of the screen door. This is a major advantage over prior art devices since one can now easily replace a broken or worn out wheel, thus increasing the useful life of the sliding door.
The present invention merely requires the user to remove the screen door from its tracks and use a small tool to pop out the wheel assembly from its holding member located on the corner mounting bracket of the frame. Once the wheel assembly is removed, a new wheel assembly can be easily snapped back onto the door by merely pushing the wheel assembly back onto its holding member. The screen door can be reset back on its tracks and the screen door will again move smoothly along its tracks.
The invention also includes a mechanism mounted to the mounting bracket that can set the "height" of the bottom wheels to properly align the stiles of the screen door with the jambs of the door opening. This adjustment mechanism allows the screen door to be properly installed within the door opening and provides an outward biasing force on the wheels to prevent the wheels from jumping from a bowed track. As a result, the sliding door remains in proper orientation with the door jambs of the door opening and moves smoothly within its tracks.